A Florida man who went hunting for pythons in Florida’s Everglades returned instead with a mysterious treasure: an antique, diamond-studded gold medallion that could date back to the 17th century.

How the handmade, penny-sized amulet got there is a riddle. One theory is it could have been aboard a ValuJet plane that crashed nearby in May 1996 – or that perhaps it was part of the debris field from an Eastern Airlines crash in the same area in 1972. The fact that it is partially melted on one side could support that idea.

But wherever it came from, Mark Rubinstein, the eagle-eyed snake hunter who found it, is determined to get it back home.

“It looks like it belongs to somebody,” he told FoxNews.com. But if the rightful owner can’t be found, Rubinstein says he’ll donate the heirloom to the Archdiocese of Miami.

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The saga of the mysterious medallion began last February when Rubinstein and two friends were participating in Florida’s state-run Python Challenge, an attempt to hunt down the invasive snakes that can reach lengths of 18 feet.

After a fruitless day, he said, “We were walking back along a levee and something in the ground just caught my eye. I walked back and forth to make sure. I walked over and dug it out of the dirt. “

Rubinstein removed an amulet that featured eight rose-cut diamonds along with gold latticework resembling a Celtic pattern. There also was a sapphire-encrusted cross in the center with engraved symbols.

“The symbols on the cross just vexed me,” he said. “I researched it but could find them anywhere.”

Rubinstein, from Coral Springs, Fla., reached out to Carroll’s Jewelers, where owner Bob Moorman confirmed the piece was likely between 18- and 24-karat gold. The rose-cut of the diamonds was popular between the 17th and 19th centuries.

Traditionally, a cross within a circle is indicative of a Celtic cross

Rubinstein also contacted the Florida Goldcoast Gem and Mineral Society, which posted photos of the piece on the popular online jeweler’s forum Ganoksin Project and various members offered theories about the religious and ethnic nature of the design.

“It looks like this cross was made sometime in the 19th century,” said Stephen Walker a New York jeweler who has joined Rubinstein’s quest to find the amulet's rightful owner. “A lot of Celtic jewelry is made to look a lot older.”

Walker estimates that if the medallion were intact, it could fetch up to a $1,000 or several hundred dollars if it were melted down for scrap metal.

“But if we could find an heir, it would be priceless,” he added.

Perry Chiaramonte is a reporter for FoxNews.com. Follow him on Twitter at @perrych